U.S. patent number 6,779,847 [Application Number 10/392,515] was granted by the patent office on 2004-08-24 for multi-task mid-pivot chair control mechanism.
This patent grant is currently assigned to L & P Property Management Company. Invention is credited to Michael N. Klein.
United States Patent |
6,779,847 |
Klein |
August 24, 2004 |
Multi-task mid-pivot chair control mechanism
Abstract
A chair control mechanism for positioning between the seat and
seat support of a chair. The chair control mechanism includes a
base section for mounting to a seat support such as an adjustable
height cylinder, and a seat mounting section pivotally
interconnected with the base section. A seat is mounted to the seat
mounting section, and is pivotal about a seat pivot axis. An
adjustable position back mounting arrangement is pivotally
interconnected with the seat mounting section, and the chair back
is engageable with the back mounting section. A variable stop
arrangement is interposed between the base section and the seat
mounting section, for varying the range of pivoting movement of the
seat relative to the seat support. The back can be selectively
locked in one of a number of predetermined positions relative to
the seat by operation of a variable position back locking
arrangement.
Inventors: |
Klein; Michael N. (Howards
Grove, WI) |
Assignee: |
L & P Property Management
Company (South Gate, CA)
|
Family
ID: |
27613843 |
Appl.
No.: |
10/392,515 |
Filed: |
March 20, 2003 |
Related U.S. Patent Documents
|
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
832776 |
Apr 11, 2001 |
6598936 |
|
|
|
Current U.S.
Class: |
297/301.2;
297/300.4; 297/300.6; 297/301.3; 297/301.5; 297/301.6 |
Current CPC
Class: |
A47C
1/026 (20130101) |
Current International
Class: |
A47C
1/024 (20060101); A47C 1/022 (20060101); A47C
001/024 () |
Field of
Search: |
;297/301.3,301.5,301.6,309,310,337,354.12,300.6,300.4,301.2 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Cranmer; Laurie K.
Attorney, Agent or Firm: Shook, Hardy & Bacon L.L.P.
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of and claims priority from
non-provisional application Ser. No. 09/832,776 filed Apr. 11,
2001, now U.S. Pat. No. 6,598,936 the contents of which are herein
incorporated by reference.
Claims
What is claimed is:
1. A back pivot arrangement for a chair control mechanism adapted
for use in a chair having a seat, a back, and a seat support
member, wherein the chair control mechanism includes a base member
secured to the seat support member and a seat mounting member
pivotally interconnected with the base member, comprising: a back
mounting member, wherein the back is adapted to be mounted to the
back mounting member; a back pivot connection interposed between
the back mounting member and the seat support member; a biasing
arrangement interposed between the back mounting member and the
seat mounting member for biasing the back forwardly relative to the
seat; and a selectively engageable variable position back locking
arrangement interposed between the seat mounting member and the
back mounting member, wherein the back locking arrangement includes
a variable position engagement arrangement, said variable position
engagement arrangement comprising a plurality of spaced openings
formed in the forward section of the back mounting member, and a
movable engagement member movably mounted to the seat support
member, wherein engagement of the engagement member within one of
the plurality of spaced openings functions to place the variable
position engagement arrangement in one of a plurality of engaged
positions.
2. The back pivot arrangement of claim 1, wherein the back mounting
member includes a back mounting section located rearward of the
back pivot connection for mounting the back to the back mounting
member.
3. The back pivot arrangement of claim 2, wherein the back mounting
member includes a forward section located forwardly of the back
pivot connection.
4. The back pivot arrangement of claim 1, wherein the movable
engagement member is biased by a spring toward a position away from
the back mounting member for placing the variable position
engagement arrangement in the disengaged position, and is movable
to the engaged position in response to movement of a manually
operated actuator engagement interconnected with the engagement
member for moving the engagement member toward the back mounting
member against the force of the biasing spring.
5. The back pivot arrangement of claim 1, wherein the biasing
arrangement comprises a back biasing spring engaged with the seat
mounting member at a first location and with the back mounting
member at a second location for biasing a rearward extending back
mounting section of the back mounting member in an upward direction
relative to the seat mounting member.
Description
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
None.
BACKGROUND AND SUMMARY OF THE INVENTION
This invention relates to a chair control mechanism, and more
particularly to various features enhancing the operation and
flexibility of a chair control mechanism of the mid-pivot type.
Various chair control mechanisms are known, for controlling the
position of a chair seat relative to a seat support, such as an
upstanding chair support pedestal. Typically, a chair control
mechanism provides a seat pivot feature for providing pivoting
movement of the seat relative to the seat support, as well as a
lockout feature for selectively maintaining the seat in a
predetermined angular position relative to the seat support. Some
types of chair control mechanisms also provide a back mounting
feature for supporting the chair back. Some designs simply support
the chair back at a predetermined position relative to the seat,
while others provide controlled movement of the back in response to
changes in the seat angle, such that the seat and back move in a
synchronous fashion upon movement of the seat.
It is an object of the present invention to provide a chair control
mechanism which functions to support both the seat and the back of
a chair. It is another object of the invention to provide such a
chair control mechanism which includes a feature for adjusting the
range of pivoting movement of the seat relative to the seat
support. Yet another object of the invention is to provide such a
chair control mechanism in which the angle of the seat can be
selectively fixed in a predetermined position relative to the seat
support. A still further object of the invention is to provide such
a chair control mechanism which provides independent movement of
the chair back relative to the seat. A still further object of the
invention is to provide such a chair control mechanism which
includes a lockout feature for the chair back, to enable the chair
back to be fixed in a predetermined angular position relative to
the seat regardless of the position of the seat relative to the
seat support.
In accordance with the invention, a chair control mechanism adapted
to be positioned between a seat support and a seat, includes a base
member secured to the seat support and a seat mounting member
pivotally engaged with the base member for movement about a seat
pivot axis. The seat is adapted to be mounted to the seat mounting
member, and an adjustable spring is interposed between the base
member and the seat mounting member for biasing the seat toward a
predetermined position relative to the seat support. A variable
position seat locking arrangement is interposed between the base
member and the seat mounting member for selectively retaining the
seat in one of a series of predetermined positions against the
force of the spring. The variable position seat locking arrangement
may include one or more locking pins interconnected with a manually
operated actuator mechanism, and each locking pin is selectively
engageable within one of a series of seat locking openings formed
in a retainer member associated with the seat mounting member. The
manually operable actuator mechanism includes a handle and an
actuator member which is operable to selectively move one of the
seat locking pins into engagement within one of the seat locking
openings.
The seat mounting member includes a back mounting arrangement for
pivotally mounting the back to the seat mounting member, for
movement about a back pivot axis. The back mounting arrangement
includes a back pivot member fixed to the seat mounting member at a
location rearward of the seat pivot axis. A back mounting bracket
is pivotally engaged with the back mounting member, so as to be
relative to the seat mounting member about the back pivot axis
which is defined by the back mounting member. With this
arrangement, the seat is pivotal about the seat pivot axis relative
to the seat support member, and the back is independently pivotal
about the back mounting member relative to the seat. A biasing
arrangement, such as a torsion spring, is interposed between the
seat mounting member and the back mounting bracket for biasing the
back forwardly relative to the seat. A variable position back
locking arrangement is interposed between the seat mounting member
and the back mounting bracket. The variable position back locking
arrangement is preferably located forwardly of the back mounting
member, and includes one or more back locking pins, each of which
is selectively engageable within one of a series of spaced openings
associated with the back mounting bracket, for selectively locking
the back at a predetermined angle relative to the seat against the
force of the spring.
The invention also includes a system for adjusting the range of
pivoting movement of the seat relative to the seat support. This
aspect of the invention involves the use of a front pivot stop
arrangement and a rear pivot stop arrangement, preferably in
combination so as to control the range of pivoting movement of the
seat relative to the seat support.
The front pivot stop arrangement may be in the form of stop
structure associated with either the base or the seat support
member of the chair control mechanism, and an engagement member
associated with the other of the base member and the seat support
member. The stop structure may be in the form of a stop member
mounted to the seat support member. The stop member defines an
upwardly facing stop surface and one or more slots extending from
the stop surface. The engagement member is preferably mounted to
the seat support member, and is shiftable between first and second
positions. In its first position, the engagement member engages the
upwardly facing stop surface of the stop member so as to limit the
forward pivoting movement of the seat support member relative to
the base member to a first angular position. When shifted to its
second position, the engagement member is aligned with one of the
slots in the stop member and is receivable within the slot so as to
enable the seat mounting member to be pivoted to a second angular
position relative to the base section. The engagement member is
preferably mounted to a manually operable handle, which can be
manipulated by a user to place the engagement member in either its
first position or its second position. The stop member and the
engagement member are preferably located forwardly of the seat
pivot member so as to control the forward pivoting movement of the
seat relative to the seat support.
Opposite the stop member and the engagement member, one or more
pivot stop members are interposed between the seat support member
and the base member for limiting pivoting movement of the seat in
the opposite direction of pivoting movement. The one or more pivot
stop members are preferably mounted to the base member rearwardly
of the seat pivot member, and each pivot stop member defines a stop
surface engageable by the seat support member when the seat support
member is pivoted relative to the base member, for limiting
pivoting movement of the seat relative to the seat support. In this
manner, the height of the stop surface of the pivot stop member
determines the angle at which the seat support member engages the
stop surface. The pivot stop member is selected from different
pivot stop members of varying height, such that the height of the
stop surface of the pivot stop member is selected according to the
desired pivot angle of the seat support member relative to the base
member, to limit the angle of the seat relative to the seat
support. In a preferred form, the one or more stop members are
selected and placed at the time of manufacture of the chair control
mechanism, and are enclosed by the structural components of the
chair control mechanism during use. The pivot stop members are
preferably employed to limit the range of rearward pivoting
movement of the seat support member relative to the base member,
and thereby the rearward pivoting angle of the seat relative to the
seat support.
The various aspects of the invention can be utilized individually
to provide selective enhancements in the features and functioning
of a chair control mechanism, or can be used in combination to
provide a chair control mechanism with significant enhancements in
flexibility in manufacture and operation.
Various other features, objects and advantages of the invention
will be made apparent from the following description taken together
with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings illustrate the best mode presently contemplated of
carrying out the invention.
In the drawings:
FIG. 1 is a side elevation view of a chair incorporating the
improved chair control mechanism of the present invention;
FIG. 2 is a bottom plan view of the chair control mechanism of the
present invention, with reference to line 2--2 of FIG. 1;
FIGS. 3 and 4 are partial section views, both with reference to
line 4--4 of FIG. 2, showing the adjustable front pivot limit
control feature of the present invention;
FIGS. 5 and 6 are views similar to FIGS. 3 and 4, showing the
variable rear pivot stop arrangement incorporated in the chair
control mechanism of the present invention;
FIG. 7 is a partial section view taken along line 7--7 of FIG. 3,
showing the variable position retainer arrangement for selectively
locking the seat in a desired position relative to the seat
support;
FIG. 8 is a partial section view taken along line 8--8 of FIG. 3,
showing the front pivot limit control feature incorporated in the
chair control mechanism of the present invention and illustrating
the engagement member shifted to a horizontal lockout position;
FIG. 9 is a partial section view taken along line 979 of FIG. 4,
showing the engagement member shifted to a position enabling the
seat support to be pivoted forwardly beyond horizontal;
FIG. 10 is a partial section view taken along line 10--10 of FIG.
5;
FIG. 11 is a partial section view taken along line 11--11 of FIG.
2, showing the pivotal back mounting feature incorporated in the
chair control mechanism of the present invention; and
FIG. 12 is a view similar to FIG. 11, showing pivoting movement of
the back mounting bracket relative to the seat support member and
retained in position using the variable position back locking
feature incorporated in the chair control mechanism of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, a chair 20 generally includes a seat 22, a
back 24, a base 26 including a seat support member in the form of
an adjustable height cylinder 28, and a chair control mechanism 30.
In a manner as is known, seat support cylinder 28 can be adjusted
in height so as to vary the elevation of seat 22 relative to a
supporting surface, such as a floor 32.
As shown in FIGS. 1 and 2, chair control mechanism 30 generally
includes a base member or section 34, a seat mounting member or
section 36, and a back mounting member or section 38. In a known
manner, base section 34 is fixed to the upper end of seat support
cylinder 28, and seat 22 is mounted to a series of seat mounting
tabs 40 forming a part of seat mounting section 36. Back 24 is
mounted to a back support bar 42, which is generally L-shaped and
includes a lower transverse mounting section 44 and an upstanding
back mounting section 46.
Referring to FIGS. 1-3, base section 34 includes a bottom wall 48
and a pair of upstanding sidewalls 50. An angled front wall 52
extends upwardly and forwardly from the forward end of bottom wall
48, and is located between and interconnects the forward ends of
sidewalls 50. A transverse reinforcing wall 54 (FIG. 3) extends
between sidewalls 50 and is oriented parallel to bottom wall 48.
Base section 34 defines an interior which is open upwardly and
rearward.
Seat mounting section 36 includes a top wall 56 and a pair of
depending sidewalls 58. A front wall 60 extends downwardly from the
forward end of top wall 56, and extends between and interconnects
the forward ends of sidewalls 58. Seat mounting tabs 40, which
extend outwardly beyond sidewalls 58, comprise the outer ends of a
pair of transverse seat mounting bars 61 secured in any
satisfactory manner, such as by welding, to the upwardly facing
surface of top wall 56. Seat mounting section 36 defines an
internal cavity which opens downwardly and rearward.
Sidewalls 58 of seat mounting section 36 are positioned so as to
overlap sidewalls 50 of base section 34. A seat pivot member, in
the form of a transverse seat pivot pin 62, extends between and
pivotally interconnects the overlapping base section sidewalls 50
and seat mounting section sidewalls 58. In this manner, seat
mounting section 36 is pivotal relative to base section 34 about a
pivot axis defined by the longitudinal axis of seat pivot pin 62.
Seat pivot pin 62 is located vertically above and aligned with the
upper end of seat support cylinder 28, such that base section 34
and seat mounting section 36 provide a mid-pivot arrangement for
seat 22 relative to seat support cylinder 28.
In a manner as is known, a spring bears between base section 34 and
seat support section 36, for biasing seat support section 36
forwardly, i.e. in a counterclockwise direction with reference to
FIG. 1. A spring tension adjustment mechanism, including a
rotatable tension adjusting knob 64, is interconnected with the
spring for adjusting the forward bias exerted on seat support
section 36.
A variable position seat locking mechanism is interposed between
base section 34 and seat mounting section 36, for selectively
locking the position of seat mounting section 36 relative to base
section 34 and thereby selectively locking seat 22 in position
relative to seat support cylinder 28. The variable position seat
locking arrangement includes a retainer member in the form of a
plate 66 secured at its upper end to the underside of seat mounting
section top wall 56. Retainer plate 66 includes a series of front
vertically spaced apertures 68 and a series of rear vertically
spaced apertures 70 which are vertically staggered relative to
front apertures 68. The seat position locking mechanism further
includes a seat lock actuator 72 (FIGS. 2, 7) which includes a
cylindrical housing 74 and an actuator handle 76 pivotally mounted
to the outer end of cylindrical housing 74 via an actuator pivot
pin 78. The inner end of cylindrical housing 74 is secured to the
outwardly facing surface of one of base section sidewalls 50 in any
satisfactory manner, such as by welding.
The construction and operation of seat lock actuator 72 is fully
disclosed and described in issued U.S. patent granted (Ser. No.
09/197,039, filed Nov. 20, 1998), the disclosure of which is hereby
incorporated by reference.
Seat lock actuator 72 includes a plunger or slider 80 located
within cylindrical housing 74. Actuator handle 76 includes a
spherical inner end 82 through which pin 78 extends, for pivotally
mounting actuator handle 76 to cylindrical housing 74. Inner end 82
includes a nose-like actuator surface 84 which is engageable with
an angled rear surface 86 provided on slider 80. In this manner,
pivoting movement of slider end 82 through operation of handle 76
results in selective forward movement of slider 80 within the
internal passage of cylindrical housing 74.
A pair of locking pins 88a, 88b are located within the internal
passage of cylindrical housing 74. Locking pins 88a, 88b include
respective outer portions 90a, 20 90b received within respective
passages 92a, 92b formed in slider 80, and locking pins 88a, 88b
also define respective inner portions 94a, 94b. Inner locking pin
portions 94a, 94b extend through respective springs 96a, 96b, which
define outer ends which are received within grooves 98a, 98b,
respectively, formed in locking pins 88a, 88b, respectively. The
inner ends of springs 96a, 96b bear against the outer surface of
base section sidewall 50, and the inner ends of locking pin inner
portions 94a, 94b extend through openings 100a, 100b, respectively,
formed in sidewall 50. A pair of springs 102a, 102b are received
within passages 92a, 92b, respectively, and bear between the
respective ends of passages 92a, 92b and the outer ends of locking
pins 88a, 88b, respectively. Springs 102a, 102b urge slider 80
outwardly and urge respective locking 30 pins 88a, 88b inwardly.
With this construction, when actuator handle 96 is moved to a
disengaged position, springs 96a, 96b push respective locking pins
88a, 88b outwardly away from retainer plate 66, to disengage
locking pins 88a, 88b from retainer plate 66.
When actuator handle 76 is moved to its engaged position, as shown
in FIG. 7, slider 80 is moved inwardly within the passage of
cylindrical housing 74 so as to compress springs 102a, 102b and to
move locking pins 88a, 88b, respectively toward locking plate 66
against the force of respective springs 96a, 96b. If one of
openings 68, 70 is in alignment with one of locking pins 88a, 88b,
respectively, the locking pin is moved into the opening under the
influence of the spring, such as spring 102a as is shown in FIG. 7,
which biases locking pin 88a into one of openings 68. If one of
openings 68, 70 is not in alignment with one of locking pins 88a,
88b, respectively, seat 22 is pivoted so as to bring one of
openings 68, 70 into alignment with one of locking pins 88a, 88b,
which results in one of locking pins 88a, 88b moving into the
aligned one of openings 68, 70, so as to fix the angle of seat
mounting member 36 relative to base section 34, and thereby seat 22
relative to seat support 28.
With the above construction, seat 22 can be freely pivoted relative
to base 28 when actuator handle 76 is in its disengaged position
and locking pins 88a, 88b are disengaged from retainer plate 66.
When desired, the angular position of seat 22 can be fixed by
moving actuator handle 76 to its engaged position and positioning
seat 22 such that one of locking pins 88a, 88b passes through one
of openings 68, 70.
The forward-most pivoting angle of seat 22 relative to seat support
28 is controlled by an adjustable forward pivot limiting mechanism
104, which generally includes a stop member 106 and a shiftable
engagement member 108. Stop member 106 is mounted to the upper end
of base section front wall 52 in any satisfactory manner. As
illustrated in FIGS. 4, 8 and 9, stop member 106 includes a
mounting section 110 defining a downwardly facing channel within
which the upper end of base section front wall 52 is received. A
pair of integral molded pins 112 secure mounting section 110 to
front wall 52 in a snap-fit manner, so as to maintain stop member
106 in position.
Stop member 106 includes a central stop 116 and a pair of end
members 118. A pair of slots 120 are defined between central stop
116 and end members 118. Shiftable engagement member 108 is mounted
exteriorly on seat mounting section 36, and includes a main body
section 122, and an inwardly extending upper arm 124 which extends
through a slot 126 formed in seat mounting section front wall
60.
Upper arm 124 terminates in an engagement section 128 located
within the interior of seat mounting section 36.
An actuator rod 130 extends through a transverse passage 132 formed
in engagement member body section 122. Actuator rod 130 is slidably
received within a pair of aligned openings formed in a pair of ears
134, which are formed integrally with the material of front wall 60
and are bent forwardly so as to extend from the forward facing
surface of front wall 60. Engagement member 108 is located between
ears 134. With this arrangement, the user can manually engage the
outer end of actuator rod 130 and exert an axial force on actuator
rod 130, which results in shifting movement of engagement member
108 along the longitudinal axis of actuator rod 130, between first
and second positions illustrated in FIGS. 3 and 4,
respectively.
When engagement member 108 is in its first position as shown in
FIGS. 3 and 8, engagement section 128 is in alignment with central
stop 116 of stop member 106. When engagement member 108 is in this
position, engagement section 128 engages the upper end of central
stop 116, as shown in FIGS. 3 and 8, to limit the forward range of
pivoting movement of seat mounting section 36 relative to base
section 34, and thereby seat 22 relative to seat support cylinder
28. Representatively, central stop 116 and engagement section 128
may be located and configured so as to provide a zero degree
forward stop for seat 22.
When it is desired to increase the range of pivoting movement of
seat 22 relative to seat support 28, engagement member 108 is
shifted to its second position as shown in FIGS. 4 and 9. With
engagement member 108 in this position, engagement section 128 is
aligned with one of slots 120 on either side of central stop
116.
Accordingly, engagement section 128 is received within slot 120
when seat mounting section 36 is pivoted forwardly relative to base
section 34, to provide an increased range of forward pivoting
movement of seat 22 relative to seat support cylinder 28. Slot 120
has a depth greater than the height of engagement section 128, such
that central stop 116 and end members 118 engage the underside of
seat mounting section top wall 56 to limit the forward pivoting
movement of seat mounting section 36 relative to base section 34,
and thereby seat 22 relative to seat support cylinder 28.
Respectively, central stop 116 and end members 118 may be located
and configured to provide a two degree forward stop for seat 22. In
this manner, the shifting of engagement member 122 functions to
limit forward pivoting movement of seat 22 to one of two
predetermined, discrete forward tilt limit positions.
Rearward of seat pivot member 62, a rear pivot stop member 136
(FIG. 3) is engaged with base section 34 for limiting the rearward
pivoting movement of seat mounting section 36 relative to base
section 34, and thereby seat 22 relative to seat support cylinder
28. Pivot stop member 136 includes an arcuate upwardly facing stop
surface 138, which extends upwardly from a disc section 140. A
mounting stub 142 extends downwardly from disc section 140, through
an aperture 144 formed in a mounting bar 146 which extends between
base section sidewalls 50. Preferably, a pair of pivot stop members
136 are mounted to mounting bar 146 at spaced locations between
sidewalls 50.
As shown in FIG. 6, the underside of seat mounting section top wall
56 engages stop surface 138 of pivot stop members 136 when seat
mounting section 36 attains a predetermined rearward pivot angle
relative to base section 34 upon pivoting movement about seat pivot
member 62. In this manner, pivot stop members 136 function to limit
the pivoting rear movement of seat mounting section 36 relative to
base section 34, and thereby seat 22 relative to seat support
cylinder 28.
The limit of rearward pivoting movement of seat mounting section 36
can be adjusted by varying the elevation of stop surface 138.
Representatively, as shown in FIG. 6, a pivot stop member 136' may
be engaged with mounting bar 146 in the same manner as pivot stop
member 136. However, pivot stop member 136' has a height greater
than that of pivot stop member 136. As shown, disc section 140' of
pivot stop member 136' has a greater height than disc section 140
of pivot stop member 136, such that stop surface 138' of pivot stop
member 136' is at an elevation above that of stop surface 138 of
pivot stop member 136. Accordingly, stop surface 138' of pivot stop
member 136' engages the underside of seat mounting section top wall
56 at a lesser angle of pivoting movement about seat pivot member
62 than pivot stop member 136, such that the limit of rearward
movement of seat 22 is less with pivot stop member 136' than with
pivot stop member 136. In this manner, the rear pivot limit of seat
22 can be controlled by selecting a desired height for the rear
pivot stop member, from a variety of pivot stop members of varying
height. Alternatively, the height of the same rear pivot stop
member can be altered, such as by adding washers or other types of
spacers between mounting bar 146 and stop surface 138 of pivot stop
member 136.
While pivot stop members 136, 136' are illustrated as being located
rearward of seat pivot member 62 and pivot limiting mechanism 104
has been illustrated as being located forwardly of seat pivot
member 62, it should be understood that an adjustable pivot limit
mechanism such as 104 may also be located rearward of seat pivot
member 62 for varying the range of rear pivoting movement of seat
22 relative to seat support cylinder 28. Likewise, it should be
understood that a variable position pivot stop such as 136, 136'
may also be located forwardly of seat pivot member 62 for
controlling the forward range of pivoting movement of seat 22
relative to seat support member 28.
Referring to FIGS. 2, 11 and 12, back mounting section 38 includes
a rear back mounting bracket 150 and a pair of spaced apart
forwardly-extending arms 152 extending forwardly from back mounting
bracket 150. Back mounting bracket 150 defines a transverse
mounting plate 154 to which lower mounting section 44 of back
support bar 42 is secured via a series of screws 156 which extend
into threaded openings in a series of mounting bosses 157 formed in
mounting plate 154, together with a pair of side flanges 158 which
depend from plate 154. Arms 152 are continuous with flanges
158.
A back pivot member 160, in the form of a headed pin, extends
between seat mounting member sidewalls 58 and through aligned
apertures formed in arms 152, to pivotally mount back mounting
section 38 to the rearward end of seat mounting section 36. In this
manner, back mounting section 38 is pivotal about a transverse
pivot axis defined by the longitudinal axis of back pivot member
160, relative to seat mounting section 36 at a location spaced
rearward from seat support cylinder 28 and seat pivot member
62.
Back pivot member 160 extends through the coil of a torsion spring
162, which defines an upper leg 164 which engages the underside of
seat mounting section top wall 56, and a downwardly extending leg
166 which engages a retainer tab 168 which is formed from an
inwardly bent section of one of flanges 158 defined by a cut-out
169. Torsion spring 162 functions to bias back mounting section 38
in a counterclockwise direction, with reference to FIG. 1, to urge
back 24 forwardly relative to seat 22.
Arms 152 of back mounting section 38 define a pair of aligned
arcuate slots 170. A stop member 172, in the form of a dual headed
pin, extends between seat mounting section sidewalls 58 and through
aligned slots 170. Engagement of stop member 172 with the ends of
slots 170 functions to control the range of pivoting movement of
back mounting section 38 relative to seat mounting section 36, and
thereby of back 24 relative to seat 22. As shown in FIG. 11,
torsion spring 162 functions to bias back mounting member 38 to a
position in which stop member 178 is engaged with the upper ends of
slots 170, which corresponds to the forward-most position of back
24 relative to seat 22.
Both of arms 152 are provided with a forward series of vertically
spaced apertures 174 and a pair of rearwardly offset vertically
spaced apertures 176. Apertures 174, 176 are aligned with a pair of
apertures in one of seat mounting section sidewalls 58. A back lock
actuator, shown in FIG. 2 at 72', is secured to seat mounting
section sidewall 58. Back lock actuator 72' is constructed
identically to seat lock actuator 72, including a pair of locking
pins 88' which extend through the apertures in seat mounting
section sidewall 58. In the same manner as described previously
with respect to seat lock actuator 72, each locking pin 88' is
adapted to be received within one of apertures 174, 176 for
selectively fixing back mounting section 38 in one of a series of
predetermined angular positions relative to seat mounting section
36, and thereby selectively locking the angle of back 24 relative
to seat 22. With this construction, back 24 is movable relative to
seat 22 independently of the angle of seat 22 relative to seat
support cylinder 28. Accordingly, the user is able to move back 24
to any desired position relative to seat 22. Back 24 can either be
locked in a predetermined position by engagement of one of locking
pins 88' within one of apertures 174, 176 when back lock actuator
72' is engaged, or can be freely pivotal relative to seat 22 when
back lock actuator 72' is disengaged.
It can thus be appreciated that chair control mechanism 30
incorporates several features which enhance the adjustability in
seat and back tilt as well as providing selective locking of the
seat and back, both separately and with respect to each other.
While the invention has been illustrated in connection with a pin
and 5 opening type of position locking arrangement, it is
understood that other types of pivot locking arrangements may be
employed, such as a friction disc arrangement or the like.
In addition, it is understood that slots 170 and stop member 172
may be eliminated and replaced with direct engagement of portions
of back mounting section 38 with seat mounting section 36 so as to
control the range of pivoting movement of back mounting section 38.
Other variations in construction and assembly details are
contemplated and known to those of ordinary skill in the art.
Various alternatives and embodiments are contemplated as being
within the scope of the following claims particularly pointing out
and distinctly claiming the subject matter regarded as the
invention.
* * * * *